Redback A 4230 User manual

www.altronics.com.au
Operating Manual
A 4230 30W Public Address Amplier
A 4240 60W Public Address Amplier
A 4250 100W Public Address Amplier
Redback® Proudly Made In Australia
OVERVIEW
These compact 1RU rack mount ampliers are suitable for both stand alone PA system use, or as zone ampliers in
larger systems requiring local inputs. All models operate on 240V ac or 24V dc for battery backup operation.
The input consists of a 3-pin XLR which can be set for either balanced mic level (3mV) or balanced line level (2V), adjusted
via a rear mounted trimpot. A dual RCA input is also provided with adjustable sensitivity of either 300mV or 1V.
Phantom power is also provided on the input XLR.
The circuit includes protection features in case of output over voltage, over current and over temperature. All are self
re-setting once the fault condition is removed. Visual indication via front panel LEDs display amplier status at all times.
FEATURES
• Compact 1RU 19” rack mount design
• Balanced mic or line input
• Phantom power
• Overload limiting
• Over voltage limiting
• On demand fan cooling (60W and 100W versions only)
• Over temperature shut down protection
• Dual input connectors
• Variable input sensitivities
• 240V ac / 24V dc operation
• Australian designed & manufactured

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2
REAR PANEL
1 2 3 4 5 6 7 8
2 1
3
Manufactured in Australia By
Altronic Distributors Pty. Ltd.
www.altronics.com.au
100V
OUT
24V DC
IN
240VAC @ 50Hz
Input 1
Balanced
Input
Sensitivty
L
R
1 2 3 4 5 6 7 8
DIP Switches
(Refer to table1)
Line Balanced
(3mV) (2V)
Resettable DC FUSE
Output
30W
Fuse
3 Amp
5 Amp
7.5 Amp
60W
100W
Mic Line
- +
+_
- +
+_
12
3
1 • Shield
2 • Hot
3 • Cold
Balanced Input
Conguration
3
24651
Table 1 : DIP Switch Settings
SW
1-6,8 Not Used
7Line input
Input Senitivity
1V 300mV
SW Input
On O
Output
30W
Fuse
1 Amp
2 Amp
4 Amp
60W
100W
AC Fuse (M 205)
RISK OF ELECTRIC SHOCK
OPEN BY QUALIFIED
PERSONNEL ONLY !
CAUTION
Volume
1 240V AC Input
Connect to a 220-240V AC @ 50Hz power source.
2 100V Output
Speakers tted with a 100V line transformer may be connected. Always ensure that the toal load of the
speakers does not exceed the rated output of the amplier ie 333Ω minimum at 100V for the A 4230 (30W),
166Ω minimum at 100V for the A 4240 (60W) and 100Ω minimum at 100V for the A 4250 (100W). Otherwise
either the DC or mains fuse could blow or the fault led activate and the amp will shut down. Always be careful
to avoid short circuits and connection to the wrong terminals. Refer to Fig 2 and Fig 3 for more details about the
impedance of speakers and how to check the impedance.
3 DIP Switch Settings
The A 4230 range of ampliers have a set of options which are enabled via the DIP switches 1-8.
Switch 1-7 Not used
Switch 8 sets the input sensitivity for the Dual RCA line input to either 1V or 300mV. Note: this only affects
the line input.
4 Audio Input
Input 1 can be used for mic or line input operation. The dual RCA line input has adjustable line input sensitivity
of either 300mV or 1V (Set by DIP switch 8). The balanced XLR input has an adjustable input sensitivity from 3mV
up to 2V. Phantom power is available on the balanced XLR input. Volume is adjusted via the volume pot on the
rear of the unit.
5 Resettable DC Fuse
Used to protect the unit when powered from 24V DC. This fuse is resettable by pressing the red button.
6 24V DC Input
Battery Backup: Provision has been provided to run the amplier from a suitably rated 24V battery system in the
event of a mains failure. Using appropriately rated cable, connect the battery to the “24V DC In” terminals.
Observe correct polarity when connecting.
Fig 1

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TROUBLE SHOOTING
If the REDBACK amplier fails to deliver the rated performance, check the following:
No Power, No Lights
Make sure amplier power switch is on. Make sure mains power switch is on at the wall. Check the mains and DC fuse.
Replace with only the correct type and rating. Over rated fuses with invalidate warranty.
Distorted Output
Check that the speaker type is correct for the output that you are using (ie. 4-16O, 70V or 100V line). Check for any short
circuits on the speaker line. Check speaker line impedance. Note you must use an inpmedance meter for this such as
Altronics Q 2001.
Very Low Output Volume
Make sure that the input is the correct level (check for shorted connectors). Check for any short circuits on the speaker
line.
Check input DIP switches are set correctly.
Continually Blows Fuses
Make sure that the speaker line is not shorted. Check speaker types, ratings and if on correct output.
Amplier Keeps on Cutting In & Out
Make sure that there is adequate ventilation around the amplier. Check the vent slots on the front,top and sides are not
covered or blocked and the fan on the rear is functioning correctly. Check also speaker types, ratings and for any short
circuits on the speaker line.
About 100V Line Speaker Systems
Wiring speakers in parallel for 100V line: Where several speakers are to be used
at one time, on one circuit, it becomes necessary to use speakers fitted with
line-matchingtransformers. This is to overcome the effects of connecting speakers
in parallel and cable losses. The amplifier generally has an output voltage of
100 volts. In this configuration the total wattage load on the amplifier is derived
from adding all the line transformer primary tap ratings together. For example, 70
one watt speakers will have a total speaker load of 70 watts. Or alternatively, it is
conceivable to connect 100 one watt speakers to a 100 watt, 100 volt line amplifier.
Measuring 100V Line Speaker Impedance: To measure amplifier system load,
you must use an impedance meter in order to measure the AC resistance of the
connected speaker network. Impedance cannot be measured with a standard multi-
meter, as this measures the DC resistance. Use the Altronics Q 2001 or similar im-
pedance meter.
70V 100V
Load System System
0.5W 9.4kΩ20kΩ
0.66W 7.12kΩ15kΩ
1W 4.7kΩ10kΩ
1.25W 3.76kΩ8kΩ
2W 2.35kΩ5kΩ
2.5W 1.88kΩ4kΩ
3W 1.56kΩ3.3kΩ
5W 940Ω2kΩ
7.5W 626Ω1.3kΩ
10W 470Ω1kΩ
70V 100V
Load System System
15W 313Ω666Ω
20W 235Ω500Ω
30W 156Ω333Ω
40W 117Ω250Ω
60W 78Ω166Ω
100W 47Ω100Ω
125W 37Ω80Ω
250W 19Ω40Ω
500W 9.4Ω20Ω
Altronics Q 2001 Impedance Meter
Fig 2
Fig 3

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SPECIFICATIONS
POWER OUTPUTS
A 4230: .................................30 watts RMS
A 4240: .................................60 watts RMS
A 4250: ...............................100 watts RMS
Distortion:..........................< 0.5%, @ 1kHz
FREQUENCY RESPONSE
Mic input:....................50Hz - 12kHz, -3dB
Line input: ..................50Hz - 15kHz, -3dB
SENSITIVITY
Mic input: ............................3mV-2V balanced
Line input:.................................300mV-1V
*Specications subject to change without notice
SIGNAL TO NOISE RATIO
Mic input: .........> 75dB below rated output
Line input:........> 81dB below rated output
OUTPUT CONNECTORS
Speakers: ...........................Screw terminals
INPUT CONNECTORS
Inputs: ........3 pin XLR balanced or 2 x RCA
24V DC power: ...................Screw terminals
240V AC power: .........IEC power connector
A 4235 30W Mixer Public Address Amplier
A 4245 60W Mixer Public Address Amplier
A 4255 100W Mixer Public Address Amplier
User manual revision number: 1.0 05/07/2013
Distributed by Altronic Distributors Pty. Ltd.
Phone: [phone] Fax: [phone] Internet: www.altronics.com.au
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